Oedemera nobilis (Scopoli, 1763)

Regarding the UK distribution Vazquez-Albalate (2003, P.103) records the observation of P.F. Whitehead that this species 'is presently in a markedly expansive and consolidational phase, which commenced during 1995', and this reflects our local experience of the species over recent decades. Between 1975 and 1987 we recorded coleoptera in west London, south Bucks and Herts which included annual visits to Cassiobury park in Watford, and during this period we did not find the species. Considering its striking appearance, size and habits it is probably very unlikely we consistently overlooked it, when we finally did find a specimen in 1985 in Parkhurst forest(IOW) we considered it something of a rarity. Upon moving to Watford in 1991 we found many specimens on Ox-eye Daisy (Chrysanthemum leucanthemium) near Radlett road and this colony thrives to the present day (2008). Buck gives 'southern England to the midlands and northern Wales', while Joy gives simply 'England, common' and the most northerly record we can find is from the Scottish borders (NBN). The species is common and usually abundant throughout our Watford area in a wide range of open habitats; Common moor, throughout the Whippendell wood/Cassiobury park area, Oxhey park and Radlett road. We have also recorded individual specimens from st Mary's churchyard and domestic gardens in the town centre. Adults are active in sunshine and frequent a very wide range of flowers where they feed on pollen and nectar. They first appear in April on whatever flowers are available and become common around the first week of May when Crataegus flowers are visited and various Umbel flowers will attract them, later on the flowers of the Yarrow (Achillea millefolium) are very attractive to them but, as stated above, a very wide range of flowers are visited. They remain common through July and usually into August. Larvae have been recorded from dry stems of Spartium and Cirsium.

6-11mm. Unmistakable; elongate and rather flattened species, bright metallic green, coppery or blue, may be distinctive. Entire upper surface with short and fine pale pubescence. Head densely and coarsely rugose, narrowed and elongate in front of eyes and with strongly narrowing temples. Eyes entire, very convex and protruding. Palpi dark metallic, terminal segment not enlarged. Antennae dark metallic or with basal segment(s) testaceous beneath, longer than elytra in both sexes, 12 segmented; basal segment curved, second very short. Inserted in front of eyes. Pronotum quadrate or slightly elongate, constricted before base, with a transverse impression before middle and a deep, wide fovea in front of base. Surface rugose and punctured, puncturation varies between specimens from large and coarse to very fine. Scutellum metallic. Elytra broadest at well developed shoulders and narrowed towards apex so that wings are visible from below base. Metallic, strongly rugose and finely punctured, with three (including sutural) longitudinal raised lines from base to apex (or near) and a shorter line from base. Apices separately rounded. Legs long and slender, metallic as body but front tibia to varying degrees testaceous. Entirely finely pubescent, male hind legs with long and dense pubescence. Hind legs dimorphic; femora strongly enlarged, tibiae angled on outer side and produced to a hook in male. Tarsi 5-5-4, penultimate segment deeply lobed.

See ID Aids for an account of the genus.

Description from nine Watford specimens

Vazquez-Albalate. European fauna of Oedemeridae. Argania, 2003